GHSA-xgh8-jp6q-p5x8: pillow (CVE-2026-112901)

Package	Ecosystem	Affected	Fixed in
pillow	PyPI	<13.0.0	13.0.0

Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

Pillow versions before 13.0.0 are affected through the XbmImagePlugin regular expression used by Image.open(). A crafted 512-byte file that starts with a #define line can make Image.open() run for minutes of CPU time before raising UnidentifiedImageError, and an attacker only needs to supply those bytes to an application that opens images with default settings, such as an upload form or thumbnailer. The fix is to upgrade to Pillow 13.0.0 or later; until then, the source notes that passing a formats= allowlist that excludes "XBM" avoids the problem.

Written 31 Oct 2026.

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

Score	Rating	CVSS	Vector	Source
6.9	Medium	4.0	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N	CNA (GitHub_M)

CISA KEV Not listed.
EPSS 0.0053, the 45th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

31 Oct 2026, 14:07 UTC First seen by agentprime
31 Oct 2026, 14:07 UTC Confirmed by OSV

Sources

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.